A common problem consumers of three-phase power supply often encounter is the “loss” of a phase. Sometimes, one (or even two) of the phases supplied by the power provider malfunctions. In such a case, consumers may use substituting power sources such as, for example, a generator in order to compensate for the “lost” phase(s). Consumers who have no alternative power provider stay without electricity which should have been provided by the “lost” phase(s).
GB Pub. Num. 367455 describes substituting sources in service. In a system, such as a ship propulsion system, having main and auxiliary generators driven by a common prime mover, such as a diesel engine, and having a second auxiliary generator which may form part of a similar set, a load circuit which has to be continuously supplied is automatically transferred from one auxiliary generator to another if the voltage of the first falls below a given value when the second machine is generating an adequate voltage.
GB Pub. Num. 396759 describes systems depending upon static transformers. A 3 phase/4 phase/3 phase overhead line transmission system in which the 4-phase high tension current is carried by at least four conductors and a ground wire, includes protective arrangements incorporating a “balanced beam ” relay whereby, on a fault occurring on a line, that line and the line carrying the “quarter-phase” associated with it are disconnected and earthed, the system then operating as a 3phase/2-phase 3 wire/3-phase system. If a spare pair of conductors is available they may replace the broken down conductor and associated line.
GB Pub. Num. 413723 describes an electric relay arrangement responsive to the phase relationship between corresponding voltages of two three-phase systems involves a mechanically balanced relay having a contact member differentially controlled by two coils respectively energized in accordance with two voltages whose magnitudes are dependent on such phase relationship.
GB Pub. Num. 597302 describes relay apparatus for connecting a network to supply mains when the voltage of the former is lower by a predetermined amount than that of the latter, comprises an induction relay having a plurality of electromagnets, one of said magnets having a winding connected across the supply mains or the network and another of said magnets having a winding supplied with current proportional to the difference in voltage between the network and the supply mains to cause the relay to operate a circuit-breaker connected between the mains and the network.
RU Pub. Num. 66619 describes three-phase power factor corrector comprising a power inverter unit, power sensors ranging power supply and control system, characterized in that the node power inverter unit consists of two power inverter modules, each of which contains six key elements included three-phase bridge circuit, three-phase inductor and a storage capacitor with a voltage sensor and control system comprises a unit ADC block determine the reference compensating current with PI voltage on the capacitor, the current PID controllers and the unit vector pulse width modulation, the output of the ADC is connected to the inputs of the block determine the reference equalizing currents with PI voltage on the capacitor, the output of which is connected via a current block of PID controllers to the input of the block vector pulse-width modulation, which is the final output block management.
RU Pub. Num. 2122273 describes a device which has three under-voltage relays with make and break contacts, correcting capacitors, phase-shifting reactors, and transient-load terminals Three newly introduced phase-correcting capacitors are inserted between phase-shifting reactors and three-phase load terminals; each capacitor is shorted out by parallel-connected make contacts of under-voltage relays of inherent and lagging phases; each phase-shifting reactor is shorted out by parallel-connected contacts of under-voltage relays of adjacent phases.
RU Pub. Num. 2340063 describes a device containing terminals of network A, B, C, three voltage-check relays with group of normally closed, group of normally open and additional group of contacts, common capacitor, phase throttles and input terminals Thus network terminals are connected to AC source, each relay is connected on phase voltage between similar phase and neutral wire. Common capacitor is connected between previous and recovered phases. Phase throttles are connected in break of corresponding phases between network terminals and input terminals. And throttle of recovered phase is bridged. Throttles of composite phases are used for additional turn of adjacent phase voltage vectors.
RU Pub. Num. 2353038 describes a device including network terminals, three voltage control relays, three phase chokes, a contact unit with two groups of contacts having common contact points and a common capacitor. The first group of contacts contains three pairs of normally closed contacts, while the first pair includes serial connection of the first relay contact with the second relay contact, the second pair—the second relay contact with the third relay contact, the third pair—the third relay contact with the first relay contact. Besides, all pair inputs are coupled with the corresponding phases, while their outputs—with common point of the first group of contacts. The second group of contacts includes also three pairs of contacts. In addition, the first pair includes serial connection of the first relay closed contact and open contact the second relay, the second pair—closed contact of the second relay contact and open contact of the third relay, the third pair—closed contact of the third relay and open contact of the first relay. Besides, inputs from all pairs are coupled with corresponding phases, while their outputs are connected to the common point of the second group of contacts. There is a common capacitor being connected between the common point of the first group and common point of the second group.
RU Pub. Num. 2551351 describes a device comprising network terminals, three fast-operate fast-release voltage relays with closing and opening contacts, seven repeater relays per a phase with closing and opening contacts, three phase-recovering capacitors, three phase-shifting chokes, three phase-compensating capacitors, terminals for the connection of a three-phase load and a power supply source. The voltage relays are coupled to phase voltage of the respective phases in the network, the phase-recovering capacitors are coupled to linear voltage, at that each of the capacitors is connected in series to an opening contact of the repeater relay of the respective phase, each of the phase-shifting chokes is shunted by the closing contacts of the first and second repeater relays of the respective phase and by the in-series closing contacts of the third and fourth repeater relays of the respective phase, the repeater relays are connected to the negative output of the power supply source directly and to the positive output through the closing contacts of the voltage relay respectively. Each phase-compensating capacitor is shunted by the closing contacts of the fifth and sixth repeated relay of the respective phase and the phase-shifting capacitor of each phase is coupled between the same phase of the network and the phase next to the retarding phase through the opening contact of the seventh repeated relay of the respective phase.
SU Pub. Num. 633110 describes an automatic redundancy arrangement for power supply source
None of the above offer to compensate for the “lost” phase(s) using the other available phase(s).
There is a long felt need for a compensation system enabling a consumer to receive a three-phase power supply in cases where one or two of the three phases malfunctions without using substituting power provider(s).